Little Wire dead bug art

Matseng was bored over the weekend and decided to make some art. He soldered up a Little Wire in dead bug style using a fine tipped soldering iron, stereo microscope, and 2 hours of his time. Check out below how this project ended up when encased in not so clear resin.

My level of boredom was not enough to actually etch a PCB for it so I did a freeform version of it. With a fine tip on the soldering iron, 0.4 mm solder, a stereo microscope and a hour or two of soldering and bending wires even an old fart like me can get the parts together without a PCB.

It all turned out rather bad. The clear 5-minute epoxy became half transparent yellowish with a lot of bubbles stuck in it even if I tried to mix the epoxy as carefully as possible. And it stuck pretty bad to the aluminum. I should have used proper clear resin specifically made for casting and also used a vacuum chamber to remove the air bubbles.

Well, It didn’t turn out exactly as I wanted, but the Little Wire works and kinda looks cool anyways so I really can’t complain too much :-)

Comments

Very cool. I love the use of surface mount like that. I’ve got a project in works using wire connected surf mount devices. It’s a rewarding challenge.

You’re right about the casting resin. A vacuum pump does wonders, along with proper mixing technique and materials. Even the clear resins for casting vary; it’s been my experience that the stuff marked ‘for industrial use only’ is the best. I use a vacuum pump to degas the ‘a’ and ‘b’ parts separately, and then carefully mix the two. The good stuff sets quickly, so it’s difficult to degas it and still pour.

Another technique is to make a silicone mold, and put the material in a pressure pot and squeeze the bubbles out. I’ve seen others have excellent results like this, but I’ve never done it.

I’ve cast quite a few various shaped clear devices with boards and LEDs in them, the clear resin is durable and allows for interesting shapes.

its for finishing tables, but ive done thick multi layer pours and it works great. and its somewhat self de-bubbling, (even better if you run a flame/heat gun over the still wet surface (the bubbles rize to the top due to density /viscosity changes and then they pop and the fluid fills in the void. no vaccum pumping needed, cures as a nice hard food safe expoxy.

Hello Adric, I really like your watch-like objet d’art, even better if it was a functioning watch! Anyway it has good aesthetics. Looking at the picture I see many tiny bubbles and while it doesn’t ruin your piece it would ruin it for the application I have in mind. Did you flame polish this pour?

@Matseng, you’ve changed my mind on dead bug style, I’ve only used this method for sake of expediency, well done.

Eff zog, no i didnt do any bubble reduction aside from blowing on it (has a similar effect due to the warmth of breath but not as well, i too want to make working ones, i did make an alarm clock with one of those as the face and hands coming up through that were lenses. its a bit finicky though. i did a little flame de bubbling on this one, although not on all layers, and i used the natural surface tension to dome up the side to look like it was a watch glass. http://www.flickr.com/photos/killbox/2970327249/

I don’t think the price of LittleWire is “outrageous” – most kits are priced with enough margin to build a sustainable business and cover any unexpected expenses. If you want a cheaper alternative the $8 Digispark is coming out soon and is electrically and software compatible with the LittleWire – you’d just need to wire up a 2×3 pin header to the digital pins and vcc and ground. It’s a really useful little gadget. They’ll probably be bootloaded with micronucleus in the future soon too so they can be software easily updated over USB with different firmwares like the cdc232 hex file.

As i replied to you at some previous blog post comment, and also as Jenna stated , the price of the Little Wire isn’t outrageous. It isn’t nothing and dirt cheap yes I’m aware of it. but there are lots of reasons behind of this price such that like small production runs, outsourcing the assembly and e-commerce work and etc. And also if you don’t like it, take an action and build your own derivative. Most people have done that. This is an open source hardware.

When you buy a kit from a OSHW developer, you are not just buying a tool but you also encourage and become a sponsor for the designer of the project. Think about it that way.

With all due respect, I disagree. Your BOM with the PCB is very likely running around $3-$4, even for small runs (significantly less for large runs). [I did an itemized BOM using Mouser.] There’s no assembly cost at all (it is a kit). If the cost of fulfillment through the likes of Seeed is the problem, – then find a better solution – Engineering is all about good solutions.

To sell this board for $19 makes it quite expensive. That’s just my opinion though, anyone is free to disagree – and I’ll be the first to defend your right to charge whatever you want for it – and my right to not buy it.

Now, if you are doing something like sharing a substantial percentage of the take with the Open Source code projects you use in your product – the situation may be very different. But I see no mention of that anywhere on your site.

From what I seen a rather common formula for calculating the retail price of a project like this is to add 40-60% to the BOM and other direct manufacturing costs to get a wholesale price that the retail channels will pay you. Then they will add another 40-60% to get the retail price for the customer.

If you sell the products yourself direct to the end users you can feel free to keep the profit from both 60% markups.

If the BOM for little wire is $4 and we go for the lowest markup it will be $4*1.4*1.4 = $7.84. The higher markup would end up as $4*1.6*1.6 = $10.24.

So looking at it naively like this I’d say that $19 is a bit high for a kit, especially if you consider that you can get a prebuilt Arduino Duemilanove for $17 with free shipping and a usb cable thrown in for good measure…

But since the Little Wire have a low cost BOM and is just doing a small production run the double 40-60% markups might not be completely relevant…. A markup of 60% of almost nothing is less than almost nothing if you look at it in real dollars instead of percentages.

Still, $19 is not too bad, and it’s open source so anyone that don’t like the price tag can make a $4 clone themselves saving $15 and having fun soldering for a while.

I don’t understand why you don’t seem to value ihsan’s time. He added features to little wire specifically to make it more useful for people buying it as a commercial kit. This isn’t something he just happened to make for himself and then made PCBs available for the fun of it. Of course it can be done cheaper if you place no value on the time spent designing, iterating, and redesigning when those ideas turned out not to be good. Patents where created to protect precisely the kind of invention Ihsan’s been doing. The littlewire firmware and desktop libraries are an original invention of Ihsan which takes time to develop, port and maintain. I’m poor so I made my littlewire deadbug with a sculpey case, but I think Ihsan’s pricing is very reasonable and littlewire has a lot of features for the price regardless of hardware costs.

Jenna, personally I don’t do my oshw stuff for profit, I even send out my pcb’s for free to anyone that asks. I do this because it’s fun.

I don’t disregard or don’t understand the efforts made by Ihsan – on the contrary I applaud his efforts developing the product and for being so daring as to make the investment/gamble to use Seeed as the “fulfillers” for it.

I wish there were some kind of easy way to send a few dollars to oshw developers whenever you make use of their design and make your own clone of it.

My QuarterK kit (an Arduino shield with a 16×16 led matrix) had a BOM cost of $6.30 and I made 200 kits at my kitchen table planning to sell them for $15. If I had calculated in the time spent on it as a cost I would had to add another $30 to each kit to cover the week I spent developing the hardware & firmware libraries, doing the purchasing and kitting.

Now I didn’t end up selling the kits due to my own laziness. I still have ~150 kits in a box, the rest I’ve given away to friends and sold a few to my local hackerspace.

Now, getting back to the retail price of LW I personally would have set the price at $9 in the hopes of getting more sales. $9 is nothing, but $19 sounds a helluva lot more and might scare away price conscious buyers. But I might be wrong here, I’m just an old tech geek and not a marketing dork. :-)

First up I declare my biased position as an OSH/OSHW supporter and advocate. I bought a LittleWire from Seeed purely to support Ihsan because it is a nice idea but especially because of the information and discussion here at DP showing more insight and excellent spirt of Ihsan! I have actually been pleasantly surprised with the LittleWire – it works really well as a programmer, and a fellow hacker at XinCheJian borrowed it for a few weeks when his long time programmer failed to program some chips!

Yes I agree the kit cost is high compared to the part cost! I would not have bought it without the extra reasons above – but this is the same for me with MANY other projects.

However as others have noted to some extent, high costs are a reality for small projects.

There are a couple of additional cost factors that I have not seen discussed above:
The cost of buying parts from digikey or mouser is just parts cost, to be able to buy a kit
– kit of parts has to be created – which includes packaging, advertising, wharehousing, support (at least for returns – I guess Ihsan is handling the technical support).
+ companies like Seeed also add value to with their reputation and also the volume site traffic can help sales.
– the setup cost / overhead becomes much higher with such a small quantity – pushing the price up further.

So there is some additional costs to be factored in to those already discussed.

Another factor that affects some people is shipping cost. From where I purchase (Australia and China), it is probably cheaper for me to buy LittleWire as a kit from Seeed than as parts major supplier due to the shipping costs. However I see from many other discussion in DP and other forums that other parts of the world have much cheaper shipping, so this varies!

I really applaud this discussion and many others in DP – as they help raise awareness of all these issues and especially increase everyone’s knowledge and capability to produce and reproduce/sell of open hardware.

I also don’t do OSHW for pure profit. At least currently … Therefore i didn’t go to mass manufacturing, shrinking the whole production costs and etc. Also if you want to make high production runs, you have buy big amount of chips and put larger amount of money to the table which I didn’t preferred to do it.

Digispark went the kickstarter way and they collected massive amount of ‘kickstart’ money. I don’t have that amount of money at the moment, therefore i can only make small production batches which then leads to high product costs.

And believe me, somehow Little Wire costs me more than 4$ in single quantities. Digikey BOM calculation isn’t a single metric for cost calculation. I also learned that in hard way.

My initial plan was to make the kitting at home and send everyone from my own Paypal cart based website, but currently I’m full time paid research student and i thought i wasn’t going to manage the shipping etc. properly and it will cost my time. Therefore i went to the Seeed for that purpose and also in order get advantage from their publicity.

To sum up, Little Wire is my first commercial OSHW product and it is an experiment for me. I paid all the production cost up-front and make a small batch available at the Seeed. I learned a lot of things on the way. Probably my next OSHW product won’t going to be that complicated and harder to explain.

And again, please look at Maker Shed. 555 timer or blinky kits goes around that same price which by the way doesn’t require that much of complicated development time. I can show you a lot examples.

If you are not happy with the price of the Little Wire please please go build one for yourself. I love when someone else creates a derivation of the Little Wire and shares it.

Just a thought for a poor man’s de-gas on the epoxy. This isn’t a perfect solution, but it does help when you have no other options and it is simple to do.

Do everything you can to make sure the two part mix is clean and free of bubbles. Mix up more of the two part than you normally would, this method isn’t efficient. Set up a tray to catch excess under where you will be doing your pour. Have one person start the pour from as high up as you can and get a thin consistent line coming down from your mixing container. Move your target container into the stream to fill it up.

The basic idea is that the thin stream streaches and degasses during the pour and what hits your target has less gas in the middle of the liquid where it can’t get out. Often little bubbles will apear near where the stream is landing. This is normal and good since these were bubble that would have been in your cast otherwise. A quick flash with a propane torch will get rid of these.

This is messy, inefficient and not a perfect solution, but it is easy to do with no extra tools by almost anyone. The results are an improvement over a basic mix and pour strategy. Hopefully this can help other people without a vacume chamber.